Pros
Usually the atmosphere is nice and relaxed. Customers are (mostly) understanding. Warehouse roles are ideal if you want to lose some weight. Some opportunity for advancement.
Cons
I had four managers, none of whom were particularly good at communicating with the rest of them. This caused a lot of employee frustration and cost time to route around problems that should never have existed. Awful managers are allowed to get away with practically anything. There's generally no recourse for complaints and usually upper management are too spineless to care. Be prepared to work harder than you've ever worked (which may or may not be a bad thing, depending on your attitude). Expect arbitrary targets and lots of them. You'll never, ever meet all of them because they're set impossibly high. Employees have to hand out Argos catalogues outside in all seasons. No sun cream is provided in Summer and you're not allowed to wear a coat/jumper in Winter. Forget having a five-minute break to drink some water because you're thirsty after talking all day. Tough. Employees are always leaving because they get treated poorly. Meanwhile, management are always complaining about employees leaving and don't seem to understand why.